Soil nutrients, such as, nitrogen, phosphorus, potassium, and sulfur, as well as trace elements such as iron, zinc, copper, and magnesium, are useful for achieving thriving agriculture and growth of the plants. However, upon repeated planting cycles, the quantity of these nutrients in the soil may be depleted as plants utilize the nutrients. Depletion of nutrient levels in the soil may result in inhibited plant growth and decreased production per acre. To counter this effect, fertilizers have been developed to help replace the depleted vital nutrients in soil so that optimal plant growth and high yields may be obtained.
Fertilizers and herbicides have typically been synthetically produced or isolated using harmful petrochemicals and other chemicals that are now being found to cause cancer, birth deformities, skin reactions and other health issues. Fertilizers and herbicides are commonly used in lawn care, gardening, agricultural, greenhouse and other plan growing environments. With concerns over the health issues related to these products and the growing demand for organic growing and organic products, corn products provide an organic solution for fertilizers and herbicides.
Fertilizers may be classified as either organic fertilizers or inorganic fertilizers. As used herein, the term “organic” generally refers to compounds including a molecular skeleton comprising a carbon backbone. Organic fertilizers are typically made from materials derived from living things. Animal manures, compost, bone meal, feather meal, and nitrogen bearing vegetable protein materials are examples of commonly used commercial organic fertilizers. Inorganic fertilizers, on the other hand, are typically manufactured from non-living materials and include, for example, ammonium nitrate, ammonium sulfate, urea, potassium chloride, potash, ammonium phosphate, anhydrous ammonia, other phosphate salts, and the like.
Chemically active herbicides represent a potential weed control technique. These chemical herbicides may be broken down into pre-emergent and post-emergent herbicides. Pre-emergent herbicides typically interfere with germination of weed seeds, whereas post-emergent herbicides kill the weeds after the weed seeds have germinated and weed growth has begun.
Pre-emergent herbicides may be effective when present at the required dosage at the time weed seed germination is ready to occur. However, this timing issue points out a major problem with respect to pre-emergent herbicides. Specifically, if the pre-emergent herbicide is not applied, or degrades, prior to weed seed germination, the weed seeds are free to germinate and begin growing into mature weeds. Additionally, pre-emergent herbicides are typically weed type specific and are not equally effective against all types of weeds. The timing problem present with pre-emergent herbicides may be avoided by employing post-emergent herbicides and by employing post-emergent herbicides only after the weed seeds have germinated and the weeds are actively growing. However, most available post-emergent herbicides are non-selective herbicides and will therefore kill desirable plants in addition to weeds. Except in the case of genetically modified crops, post-emergent herbicides cannot be used in proximity to crops.
Many pre- and post-emergent herbicides also suffer from another problem. Specifically, many pre-emergent and post-emergent herbicides are either moderately or highly toxic to humans and animals, and may thereby have damaging effects far beyond the intended weed control effect. Toxic herbicides may cause injury either immediately or over the long term to persons applying the herbicides and to persons present when the herbicides are applied. Also, residual concentrations of toxic herbicides that remain in the soil or water after application of the herbicide may pose a significant threat to human beings and to animals, including land-based animals and amphibians and fish, upon contact with the treated area or runoff from the treated area. Furthermore, public alarm about the use of toxic chemicals as herbicides and their potential widespread and long-term effects on environmental quality dictate against the continued use of these toxic herbicides. Uses of chemical herbicides are not permitted in high value organic agriculture.
A drawback of chemically active herbicides coupled with chemical fertilizer, known as weed and feed mixtures, is that they require multiple components. In addition to the serious and harmful side effects of these chemicals, they often require separate applications, have shorter periods of action, and require specially trained personnel to apply, handle, and clean up the material. Another drawback of chemically active herbicides is that they may damage mycorrhiza symbiotic fungal relationship and other beneficial soil life. Chemical fertilizer may be toxic to beneficial soil organisms, for example earthworms, humus, and related organic matter. Destruction of these compounds reduces the ability of the soil to retain nutrients.
Organic vegetable growers do not use chemical herbicides or genetically modified crop varieties in their production. One of the weed control strategies used in the production of high value organic vegetables is the use of corn gluten meal. Testing by organic farmers has shown that corn gluten meal works as a pre-emergent herbicide on a wide variety of broadleaved weeds and some grasses. A pre-emergent herbicide works well for certain types of vegetable production where transplanting is the norm. The herbicidal effects of corn gluten meal seem limited to germinating seed and does not affect most transplanted crops.
Organic fertilizers, on the other hand, are typically not immediately available to plants and require soil microorganisms to break the fertilizer components down into simpler structures prior to use by the plants. This break-down occurs over a time period and may provide for slower release of nutrients.
A relative newcomer to organic farming, corn gluten meal recently emerged as a useful byproduct of the corn milling process for use as an herbicide and fertilizer. Researchers patented the corn gluten meal as a weed control substance in 1991, but it also has other benefits. Most garden centers sell it in large bags in powdered form. While it also forms some or all of pet and cattle food products, corn gluten meal shouldn't be confused with the edible corn meal found in supermarkets.
Corn gluten meal organically inhibits the reproduction of weed seeds in lawns and gardens. The product falls into the family of herbicides known as “pre-emergent” weed killers. Once the weed seeds germinate, and the plants emerge, corn gluten meal has no effect as a weed killer. In fact, its nitrogen content actually acts as a weed fertilizer once the seeds germinate, so timing of the applications for weed control must be carefully controlled. Effective weed prevention with Corn gluten meal is generally recommended using applications of 20 pounds (lbs.) of the product per 1,000 square feet.
Corn gluten meal contains 10 percent nitrogen by weight. Thus, applying 20 lbs. of corn gluten meal for every 1,000 square feet of garden or lawn achieves the commonly recommended 2 lbs. of nitrogen for that area of land. Because that amount corresponds to the recommended rates for organic weed control, it's possible to use one application of corn gluten meal as both a fertilizer and herbicide. The product slowly releases nitrogen into the soil for three to four months.
The primary issue with corn gluten meal used in fertilizers and herbicides is that many of the components within corn gluten meal are not water soluble. For example, corn gluten meal includes water insoluble zein proteins and other insoluble fractions. The issue that corn gluten meal may require many weeks to break down and provide nitrogen and herbicide values greatly limit its effectiveness.
In order for nitrogen to be released, proteins within the corn gluten meal breakdown or undergo a hydrolyzation process, which can take a significant period of time and weather effects to fully break down. In addition, corn gluten meal is a commonly used animal feed and in some cases a human food thus taking away from this food source. In addition gluten meal is limited in the form it is produced, primarily granular forms. Attempts have been made to pelletize this corn gluten meal which also requires some type of “binder” such as sugars or other forms of binders. This further inhibits the release rates and breakdown of the corn gluten material.
The wet milling of corn produces corn gluten meal as one of its primary products. Corn gluten meal is one of many products extracted from corn during the wet milling process. A description of processes that produce corn meal is seen in U.S. Pat. No. 6,610,867 to Jakel et al. which is hereby incorporated by reference in its entirety. Other descriptions are seen in U.S. Pat. No. 6,703,227 to Jakel et al, U.S. Pat. No. 6,545,191 to Stauffer, and U.S. Pat. No. 6,509,180 to Verser which are hereby incorporated in their entireties by reference. Corn gluten meal is extracted from corn following an acid bath soaking period. Corn gluten meal may be spread on the surface of the soil after seeding or tilled in shallowly prior to seeding. The weed suppression effect of corn gluten meal continues for weeks after application. The use of corn gluten meal in this fashion is permitted for use in organic agriculture. The National Organic Standards Board (NOSB) lists corn gluten meal as a organic approved herbicide in the restricted class. However, the corn from which the corn gluten meal is derived cannot be a genetically engineered variety.
Another drawback with the use of corn gluten meal as an herbicide has been its relatively high cost. Corn gluten meal has been in high demand, especially in Europe, as both chicken and cattle feed. Corn gluten meal may produce brightly colored yokes when fed to laying hens and this is a consumer preference.
The prior art also teaches of chemical modifications to corn gluten meal using various acid treatments to create a corn hydrolysate which has been shown to have improvements for bioherbicide applications. This requires significant additional processing, cost and processing with potentially harmful chemicals. Corn gluten meal in its raw form is currently an expensive ingredient commonly used in animal food and further chemical process further adds to its cost.
U.S. Pat. No. 5,290,757 found that hydrolyzed proteins from corn gluten meal provide improvements over standard corn gluten meal. This requires further processing of the corn gluten meal by means of a secondary process adding various enzymes and corn hydrosylate.
Alternatives to corn gluten meal have been evaluated. For example, U.S. Pat. No. 7,183,237 to Blume teaches a method for the usage of distillers grain as a herbicide and fertilizer. This method uses standard dried distillers grains (DDG) which is the water insoluble fraction of the well known corn-to-ethanol production process. Although less expensive than corn gluten meal, DDG has less nitrogen bearing proteins and high percentages of water insoluble corn fiber which is not as effective as corn gluten meal.
Thus there is a need for a low cost water soluble form of organic corn protein with high nitrogen bearing content and a very high degree of water solubility that can be produced in a wider range of formats from pellets, sheets, granular and other forms. In addition, there needs to be a material with self binding nature wherein other additives can be added to modify the nature of an organic fertilizer and herbicide materials and related process. In addition there needs to be a solution that is both effective and lower cost than corn gluten meal as to better promote the usage of organic and chemical free fertilizer/herbicides.